FLOOD WATCH IN EFFECT FROM 2 PM EDT THIS AFTERNOON THROUGH THIS EVENING. * WHAT. Flash flooding caused by excessive rainfall is possible. * WHERE. Portions of DC, Maryland and Virginia, including the following areas: in DC, District of Columbia. In Maryland, Anne Arundel, Calvert, Central and Southeast Howard, Central and Southeast Montgomery, Charles, Northwest Howard, Northwest Montgomery, Prince Georges, Southern Baltimore and St. Marys. In Virginia, Albemarle, Arlington/Falls Church/Alexandria, Culpeper, Eastern Loudoun, Fairfax, Greene, King George, Madison, Nelson, Northern Fauquier, Orange, Prince William/Manassas/Manassas Park, Rappahannock, Southern Fauquier, Spotsylvania, Stafford and Western Loudoun. * WHEN. From 2 PM EDT this afternoon through this evening. * IMPACTS. Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. * ADDITIONAL DETAILS. - Showers and numerous thunderstorms are expected later this afternoon through this evening. Rainfall amounts will average around 1 to 1.5 inches across the area, but locally higher amounts of 2 to 4 inches are likely and much of that may fall in a one to two hour timeframe. Heavy rain in short periods of time may cause creeks and streams to rapidly rise out of their banks along with potential flash flooding in urban areas. - Visit http://www.weather.gov/safety/flood for flood safety information.